question

Hi @Prevost XLII, welcome to the Community!

This condition is most likely caused by a load being connected directly to the battery, thereby bypassing the BMV-712 shunt and, since the shunt can't measure anything that doesn't run through it, not being counted against your displayed SOC.

Please consult the manual and correct the BMV-712 wiring so that the "battery" side of the shunt is the the one and only thing connected to the battery bank NEG, with all other system NEGs connected to the "loads and chargers" side.

Hi @Prevost XLII

That 'nanm' in the Time Remaining field is possibly related. I suspect it's some error message, although I can't seem to find anything in the manual, and even google can't find anything definitive.

I'd try powering the BMV down by removing it's power supply cable and reinstating. Check the fuse there too, and what amperage it actually is (from memory some of these were incorrectly supplied from new).

Note the SOC before you disconnect and you can manually reinstate that after reconnecting (ideally sync to 100% when you're sure the batts are fully charged).

That's a lot of battery too, and the issue may be related to a bms. You have detail on that? A screenshot of the BMV settings might be useful too.

Hi there. Have you perhaps miscalculated your battery capacity? Eg 4 x 100Ah cells in series is only 100Ah at 12 volts...Your battery may be only 600Ah, a more reasonable capacity for an RV????

If so, your reading of about 75% SOC is exactly what you would expect when battery was empty, and 9V is definitely empty!

Just a thought, cheers, Leslie